Insulated actuator for movable electrical contact



y 11, 1965 A. H. GREBE 3,183,334

INSULATED ACTUATOR FOR MOVABLE ELECTRICAL CONTACT Filed Oct. 18, 1962 2 Sheets-Sheet 1 P RIO R A RT //fl l N!B GAP Z2 l w J ll 25/ WASTE 1 /7 H T 25 CLEARANCE PRIOR ART -2 PRIOR ART PRIOR ART IN VENTOR A: FRED 6/2555 May 11, 1965 A. H. GREBE 3,183,334

INSULATED ACTUATOR FOR MOVABLE ELECTRICAL CONTACT Filed Oct. 18, 1962 2 Sheets-Sheet 2 mvzmon 144/750 /7. 5/9555 ATTORNEY United States Patent Ofi Fice 3,l$3,334 Patented May 11, 1965 3,183,334 HISULATED ACTUATOR FUR MQVABLE ELECTRICAL CGNTACT Alfred H. Grebe, Cheshire, Comm, assignor to Allied Control Company, Inc, New York, N.Y., a corporation of New York Filed (let. 18, 1962, Ser. No. 231,373 Claims. ((11. filth-166) This invention relates to the art of electrical devices and, more particularly, to an improved insulated type of actuator for operating an element of an electrical device, such as a movable contact arm of a relay.

The actuator of this invention has wide application. It is especially useful in the field of electric relays where requirements for miniaturization and sub-miniaturization severely restrict available space for individual components. This is exemplified by a sub-miniature relay which is being presently manufactured by Allied Control Company, Inc, New York, New York, and marketed under the designation S type relay. One form of the S type relay includes a two pole double throw switch arrangement including a pair of insulated actuators for operating corresponding movable contact units. The overall size of this relay, defined by its base plate and cover, is approximately 0.4" wide by 0.4 high by 0.8" long, requiring only about one-eighth of a cubic inch of space.

The type of actuator commonly employed heretofore i1 relays of the character mentioned above generally comprises a relatively stiff wire rod, which is made of a suitable gauge metal, and a glass bead at the free end of the rod. The bead is usually spherical but may be cylindrical. In either case, the bead is joined to an end of the rod and projects beyond that end and all sides of the rod.

A principal objection to present day actuators of the indicated type is that they require space which is not necessary for proper functioning and operation and, as a consequence, frequently and appreciably limit overall miniaturization. The actuator of this invention successfully overcomes this objection, as will be clear from the accompartying drawings and the detailed description that follows.

As will also be clear from the drawings and the detailed description, the actuator of this invention afiords a number of worthwhile advantages over conventional actuators, including the following:

(1) The subject actuator has a substantially lower profile, while affording requisite structural strength and electrical characteristics, than comparable conventional actuators. This minimizes space requirements;

(2) The insulating bead member of the actuator of this invention, whether a glass head or an equivalent element, is more securely afiixed to its rod than the glass beads of conventional actuators. This virtually eliminates the possibility of the bead becoming fractured or detached from its rod in the course of assembly and adjustment; and

(3) The present actuator is easier to manufacture and less expensive than comparable conventional actuators.

It is the primary object of this invention to provide an actuator for electrical devices having improved features of design and construction.

Another object of this invention is to provide an actuator of the character indicated which is compact and lightweight in design; which is sturdy and durable in construction; which possesses requisite structural strength and electrical characteristics; which is reasonable in manufacturing cost; and which is capable of performing its intended functions in a dependable and trouble-free manner.

The enumerated objects and additional objects will be readily understood by persons trained in the art from the accompanying drawings and the following description which illustrate and describe two forms of prior art actuators and two forms of actuators embodying the invention.

In the drawings, wherein like reference characters denote corresponding parts throughout the several views and wherein the various parts are greatly enlarged for purposes of illustration:

PEG. 1 is a view in elevation of a portion .of a relay including a prior art actuator, certain parts being shown in cross-section for better illustration;

FIG. 2 is an elevation view of the actuator shown in FIG. 1;

PEG. 3 is a view taken along line 33 of FIG. 2;

FIG. 4 corresponds to FIG. 2 and illustrates another form of prior art actuator;

FIG. 5 is a view taken along line 55 of FIG. 4;

FiG. 6 is a top plan view of an actuator rod constructed in accordance with this invention, this rod being a part of the complete actuator shown in FIG. 8;

FIG. 7 is a side elevation view of the actuator rod of FIG. 6;

FIG. 8 is a top plan view of one form'of actuator constructed in accordance with this invention;

FIG. 9 is a side elevation view of the actuator of FIG. 8;

FIG. 10 is a view taken along line lti10 of FIG. 9;

FIG. 11 is a top plan view of another form of actuator constructed in accordance with this invention;

FIG. 12 is a side elevation view of the actuator of FIG. 11; and

FIG. 13 is a view taken along line 13-43 of FIG. 12.

Merely by way of example, there is shown in FIG. 1 a portion of a conventional relay 15 which includes a prior art actuator A4. The illustrated portion of the relay includes a header assembly H which serves as a support means for various components and which comprises a base plate 16 and a plurality of fixed electric terminals, only one of which is shown and designated by numeral 17. These terminals extend through the base plate and are affixed thereto by corresponding masses of a suitable, rigid, insulating material, such as glass, as indicated at 18. A stationary contact element 19 is provided at the upper end of terminal 17. Each terminal 17 and its contact element 19 constitute a stationary electric contact unit.

The header assembly also comprises at least one movable contact in the form of an electrically conductive leaf spring contact arm 20 which is positioned above and in spaced relation to base plate 16. One end of contact arm 20 is secured to an electrically conductive fixed support 21 which is carried by the base plate- The other end of the contact arm is equipped with a contact button 22 which is positioned directly above contact element 19. Arm 2% and its contact button 22 constitute another electric contact unit and are so constructed and arranged that contact arm 20 normally and yieldingly maintains contact button 22 in cont act with contact element 19, as shown.

Interposed between base plate 16 and contact arm 20 is a portion of an armature 23 and an actuator A-1 which is secured to the armature by welding or in any other desired manner known to the art. illustrated relay, is pivotal about a horizontal axis (not shown) and is so configured and arranged as to impart upward swinging movement to the free end of the actuator upon energization of the relay.

Actuator A1 consists of a cylindrical wire rod 24 and a spherical glass bead 25 which is secured by fusing to the free end of the rod. Upon energization of the relay, glass bead 25 moves upwardly, engages the underside of contact arm 29 and flexes the contact armupwardly, thereby breaking contact between the contact button 22 and contact element 19.

The armature, in the" Certain distances or spaces are labeled in FIG. 1 by the expressions Nib Gap, Clearance and Waste. Nib Gap identifies the space between the top of glass bead 25 and the undersurface of movable arm 2% and is required to allow for contact erosion and vibration clearance in use. Thespace or distance labeled Clearance is also required between the actuator, i.e., the bottom of the glass bead, and the base plate, both as a manufacturing necessity and to allow for vibration in use. Waste? indicates the space required for the portion of the glass head which is below the actuator rod 24. This is true 'Waste space since no insulation is actually needed between the actuator rod and the base plate; and, therefore, no space is needed between the actuator and the base plate other than the space labeled Clearance.

FIGS. 4 and 5 illustrate another form of prior art actuator A.-2 which is the same as actuator A-l except that it utilizes an elongated glass bead 26 in place of earlier described spherical glass bead 25. Glass head comprises a cylindrical central portion 27 and rounded end portions 28 and 29. As in the case of actuator A-l, the portion of actuator A 2. which is between its rod 24 and the relay base plate, or other structural element, represents Waste.

An actuator constructed in accordance with the present invention eliminates the Waste space referred to above in that no portion of the insulating element,

7 whether a glass bead or a head of some other suitable material occupies any of the space between the actuator rod and a structural element of the relay, such as the header base plate shown in FIG. 1.

Referring to FIGS. 6 through 10, the actuator A-Ii, which is illustrated therein, comprises a relatively stiff wire rod 30 consisting of a shank or body portion 31 and an end portion 32 which is bent in the form of .a generally circular loop 32 that defines a through opening 33. This actuator also comprises a head 34 of a suitable electric insulating material, preferably glass, whichconsists of a generally semi-spherical body 35 and an integral stem 3d. The bead 34 is pre-formed and is mounted on rod portion 32 with its stem 35 in registry with opening 33. The bead is then firmly affixed to rodend portion 32, preferably by fusing, which causes firm adher ence of body 35 to the outer face of rod portion 32vand.

like adherence of the stem 36 to the portions of the rod which define opening 33. bead to the rod, part of the material of the stem flows so as to conform to the configuration ofthe opening, as indicated in FIG. 10, to thereby firmly anchor the bead to the rod. The construction, configuration and relationship of the parts of actuator A-3 are believed to be fully andclearly illustrated in FIGS. 8 through 10.

There is illustrated in F163. 11 through 13 another form of actuator A-4 which is constructed in accordance with this invention. This actuator is closely related to that of FEGS. 8 through 10 and comprises a wire rod 37 consisting of a shank 38 and an end portion 39 which is bent in the form of an elongated loop that defines a through opening 40. Actuator A-4 is also'provided with an insulating bead, preferably of glass, and consisting of an elongated body portion 42, which is rounded at its ends, and a stem 43. The procedure in assembling and uniting the parts of actuator A-4- is the same as that outlined earlier herein with reference to actuator A-3.

The wire rods of actuators A-3 and A-4 are made of a suitable metal having a coefiicient of expansion which In the course of fusing the is substantially equal to that of the corresponding insulating bead. One of the metals commonly used in making actuator rods is commercially available under the trade name Kovar.

It will be appreciated that the bead may be anchored to its rod in any desired manner known to the art. While conventional fusion is preferred, it should be borne in mind that the parts may be united by employing other procedures including the use of suitable synthetic plastic compositions for obtaining an adequate bond between the parts.

From the foregoing, it is believed that the objects, advantages, construction and utility of the present invention will be readily comprehended by persons skilled in the art without further description. Although the invention has been herein shown and described in two simple and practicable forms, it is to be understood that the invention is not to be limited to the exact details described herein, but is to be'accorded the full scope and protection of the appended claims.

I claim: q

l. in an electrical device, support means, first and second electric contact units carried by the support means, at least a portion of the second contact unit being aligned with and movable relative to the first contact unit, and an actuator carried by the support means and movable relative to the contact units, said actuator being engageable with the second contact unit and operable to effect predetermined movement of said portion of the second contact unit relative to the first contact unit, said actuator comprising an elongated rod of substantially uniform cross sectional area throughout its length including a looped end part -forming an opening and an electrical insulating member including a body bearing against and projecting substantially wholly beyond one side of said end part and a stem secured tothe 'body, said stem registering with said opening and bearing against portions of said end part which define said opening, said body of the insulating member being the only portionof the actuator which is engageable with the second contact unit.

-2. An electrical device according to claim 1 wherein the rod is substantially stiff and consists of a metal having a coefficient of expansion which is substantially equal to that of the insulating member.

3. An electrical device according to claim 1 wherein said end part comprises a bent portion of the rod.

4. An electrical device according to claim 1 wherein said opening extends through the central portion of said end part.

5. An insulated actuator for use with a movable electrical contact comprising an elongated rod of substantially uniform cross sectional area throughout its length including a looped end part forming an opening and an electric insulating member including a body bearing against and projecting substantially wholly beyond one side of said end part and a stem registering with said opening and bearing against portions of said end part which define said opening.

References Cited by the Examiner UNlTED. STATES PATENTS 3/58 Girdwood et al ZOO-37 10/ 6l Brunicardi 200-404 BERNARD A. GlLl-lEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner. 

5. AN INSULATED ACTUATOR FOR USE WITH A MOVABLE ELECTRICAL CONTACT COMPRISING AN ELONGATED ROD OF SUBSTANTIALLY UNIFORM CROSS SECTIONAL AREA THROUGHOUT ITS LENGTH INCLUDING A LOOPED END PART FORMING AN OPENING AND AN ELECTRIC INSULATING MEMBER INCLUDING A BODY BEARING AGAINST AND PROJECTING SUBSTANTIALLY WHOLLY BEYOND ONE SIDE OF SAID END PART AND A STEM REGISTERING WITH SAID OPENING AND BEARING AGAINST PORTIONS OF SAID END PART WHICH DEFINE SAID OPENING. 